Given the task definition and input, reply with output. In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.

A tornado emergency is an enhanced version of a tornado warning , which is used by the National Weather Service ( NWS ) in the United States during imminent , significant tornado occurrences in highly populated areas .

A tornado emergency is a stronger wording of tornado warnings used by the National Weather Service in the United States .